1. Field of the Invention
The present invention relates to an electrolytic processing device for metal strips. More specifically, the invention relates to an electrolytic processing device applicable to electrogalvanizing lines, electrotinning lines, electrolytic chromium processing, phosphorate processing, chromate treatments and so forth. The invention relates to a novel device for electrolytic processing of the surface of a metal strip.
2. Description of the Prior Art
So-called "radial-type" electrolytic processing devices are well-known in the field of metal strip surface treatment. In these electrolytic processing devices, a strip-shaped metal piece is fed along a meandering path defined by a plurality of rollers. During its travel, the metal strip is dipped into an electrolytic solution or electrolyte in an electrolytic tank. Within the electrolytic solution, an electric current is applied to the metal strip to induce electrolysis.
Recently, a great variety of surface treatments have been applied to metal strips. For example, even considering only electrogalvanization, not only pure zinc but also composites of zinc and iron, zinc and nickel and so forth are used as plating agents. Different electrolytic solutions are required for each separate plating process and plating agent. In other words, when two different electrolytic solutions are mixed, the efficiency of the solution drops significantly, which degrades plating quality.
Therefore, in conventional processes, when an electrolytic process is to be performed with a different plating agent, the electrolytic agent for one plating agent has to be drained completely before using another electrolytic solution adapted for another plating agent in the same electrolytic tank. It is standard practice as well to clean or wash the tank after draining one solution and before adding the next in order to completely avoid mixing of different solutions.
This clearly lowers the efficiency of the production line and thus increases the cost of electrolytic processing.